A207756 Number of 7Xn 0..1 arrays avoiding 0 0 1 and 0 1 1 horizontally and 0 0 1 and 1 0 0 vertically.

35, 1225, 7210, 42436, 147084, 509796, 1341606, 3530641, 7826035, 17347225, 34169660, 67305616, 121583280, 219632400, 371285460, 627652809, 1006704699, 1614673489, 2481460982, 3813556516, 5656542892, 8390193604, 12078020682

Offset: 1

Author

R. H. Hardin Feb 19 2012

Keywords

• nonn

Comments

Row 7 of A207752

Examples

			Some solutions for n=4
..0..0..0..0....1..0..0..0....1..0..1..0....0..0..0..0....1..0..1..0
..0..1..0..1....0..0..0..0....1..1..0..1....1..1..1..1....1..0..0..0
..0..0..0..0....1..0..0..0....1..1..1..1....0..0..0..0....1..0..1..0
..0..1..0..1....0..0..0..0....0..1..0..0....1..1..1..1....1..0..0..0
..0..1..0..0....1..0..0..0....1..1..1..1....1..0..1..0....1..0..1..0
..0..1..0..1....0..0..0..0....1..0..0..0....0..1..0..1....0..0..0..0
..0..1..0..0....1..0..0..0....1..1..1..1....1..0..1..0....1..0..1..0
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 2*a(n-1) +8*a(n-2) -18*a(n-3) -27*a(n-4) +72*a(n-5) +48*a(n-6) -168*a(n-7) -42*a(n-8) +252*a(n-9) -252*a(n-11) +42*a(n-12) +168*a(n-13) -48*a(n-14) -72*a(n-15) +27*a(n-16) +18*a(n-17) -8*a(n-18) -2*a(n-19) +a(n-20)